Sensor mounting system

ABSTRACT

A sensor mounting assembly is configured for use with a vessel arrangement including at least four vessels. The assembly includes first and second elongated frame members, first and second rollers, and first and second sensors. The first sensor is attached to the first elongated frame member and is configured to contact the surface of the first vessel upon actuation in a first direction. The second sensor is attached to the second elongated frame member and is configured to contact the surface of the second vessel upon actuation in a second direction that is substantially orthogonal to the first direction. This disclosure also describes a method of mounting at least six sensors for use with a vessel arrangement including at least four vessels, the vessel arrangement disposed in a container in a two-by-two stacked configuration having a central space.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.16/190,303, filed Nov. 14, 2018, which claims the benefit of priority ofU.S. Provisional Patent Application Ser. No. 62/585,671, filed Nov. 14,2017; the contents of these priority applications are fully incorporatedherein.

BACKGROUND

Pressure vessels are commonly used for containing a variety of gases orfluids under pressure, such as hydrogen, oxygen, natural gas, nitrogen,propane and other fuels, for example. Generally, pressure vessels can beof any size or configuration. The vessels can be heavy or light,single-use (e.g., disposable), reusable, subjected to high pressures(greater than 50 psi, for example), low pressures (less than 50 psi, forexample), or used for storing fluids at elevated or cryogenictemperatures, for example.

Suitable pressure vessel shell materials include metals, such as steel;or composites, which may be formed of laminated layers of woundfiberglass filaments or other synthetic filaments bonded together by athermo-setting or thermoplastic resin. A liner or bladder is oftendisposed within a pressure vessel shell to seal the vessel, therebyserving as a fluid permeation barrier.

Generally, pressure vessels have limited lifetimes, and it is desirableto remove a pressure vessel from service before it fails. Both cyclicfatigue and static fatigue (stress rupture) contribute to the fatigueload, and thus the failure, of pressure vessels. The calendar life of apressure vessel, or the number of fatigue cycles over a specificpressure range (for example, from near empty to full), is commonly usedto determine when to remove a vessel from service. However, in someapplications, the pressure ranges and number of cycles applied to thepressure vessel are inconsistent and/or unknown. In addition, theinteraction between cyclic fatigue life and static fatigue life is notfully understood. The effects of cycling combine in unknown ways withthe effects of the duration the pressure vessel spends at full pressure.

Mathematical projections of vessel lifetime are commonly used toevaluate the fatigue life of a pressure vessel. This requires that thenumber of cycles be counted or estimated, then sorted by mean stresslevels and stress range. These cycles are combined into an equivalentnumber of full-range cycles to estimate the remaining vessel life. Itmust then be determined how to combine this information with staticfatigue. Uncertainties are inherent in the calculation and estimation ofcycles, in combining cycle effects, and in assessing the projected totaland remaining life of the pressure vessel.

Another way to assess the estimated useful life remaining in a pressurevessel is to use sensors to gather information on the pressure vessel'sphysical characteristics. Suitable sensors include Modal AcousticEmission (MAE) sensors, for example. Such ultrasonic sensors areavailable from Digital Wave Corporation of Centennial, Colo. Ultrasonicwave propagation can be evaluated in bulk and “thin-walled” solidmaterials to assess the structural integrity of the materials. Due tothe variation in stiffness as a function of propagation angle (i.e.,material anisotropy), which is commonly observed in composite materials,significant effects in wave propagation characteristics are observed.Thus, such material anisotropy must be accounted for in the wave formanalysis. Laminates further complicate this analysis because of themultiple material interfaces that should be considered. Analysis of suchwave forms can lead to information regarding fiber fracture, matrixcracking, and interfacial delamination, for example.

SUMMARY

In one aspect, this disclosure describes a sensor mounting assemblyconfigured for use with a vessel arrangement including at least first,second, third and fourth vessels. The sensor mounting assembly includesfirst and second elongated frame members, first and second rollers, andfirst and second sensors. The first roller is attached to the firstelongated frame member and is configured to contact and roll upon afirst surface of one of the first, second, third and fourth vessels. Thefirst sensor is attached to the first elongated frame member and isconfigured to contact the surface of the first vessel upon actuation ina first direction. The second elongated frame member is connected to thefirst elongated frame member. The second roller is attached to thesecond elongated frame member and is configured to contact and roll upona second surface of one of the first, second, third and fourth vessels.The second sensor is attached to the second elongated frame member andis configured to contact the surface of the second vessel upon actuationin a second direction that is substantially orthogonal to the firstdirection.

In another aspect, this disclosure describes another embodiment of asensor mounting assembly configured for use with a vessel arrangementincluding at least first, second, third and fourth vessels. The vesselarrangement is disposed in a container in a two-by-two stackedconfiguration having a central space. The sensor mounting assemblyincludes a top rail assembly, an upper interior rail assembly, a lowerinterior rail assembly, and a bottom rail assembly. The top railassembly is attached to the container proximate a top of the containerand is configured to position a first sensor proximate the first vessel.The upper interior rail assembly is positioned in the central space andis configured to position a second sensor proximate the first vessel anda third sensor proximate the second vessel. The lower interior railassembly is positioned in the central space and is configured toposition a fourth sensor proximate the third vessel and a fifth sensorproximate the fourth vessel. The bottom rail assembly is attached to thecontainer proximate a bottom of the container and is configured toposition a sixth sensor proximate the fourth vessel.

In yet another aspect, this disclosure describes a method of mountingfirst, second, third, fourth, fifth, and sixths sensors for use with avessel arrangement including at least first, second, third and fourthvessels, the vessel arrangement disposed in a container in a two-by-twostacked configuration having a central space. The method includesattaching a top rail assembly to the container proximate a top of thecontainer to position a first sensor proximate the first vessel;inserting an upper interior rail assembly into the central space toposition a second sensor proximate the first vessel and a third sensorproximate the second vessel; inserting a lower interior rail assemblyinto the central space to position a fourth sensor proximate the thirdvessel and a fifth sensor proximate the fourth vessel; and attaching abottom rail assembly to the container proximate a bottom of thecontainer to position a sixth sensor proximate the fourth vessel.

This disclosure, in its various combinations, may also be characterizedby the following listing of items:

-   1. A sensor mounting assembly configured for use with a vessel    arrangement including at least first, second, third and fourth    vessels, the sensor mounting assembly including:    -   a first elongated frame member;    -   a first roller attached to the first elongated frame member, the        first roller configured to contact and roll upon a first surface        of one of the first, second, third and fourth vessels;    -   a first sensor attached to the first elongated frame member and        configured to contact the surface of the first vessel upon        actuation in a first direction;    -   a second elongated frame member connected to the first elongated        frame member;    -   a second roller attached to the second elongated frame member,        the second roller configured to contact and roll upon a second        surface of one of the first, second, third and fourth vessels;        and    -   a second sensor attached to the second elongated frame member        and configured to contact the surface of the second vessel upon        actuation in a second direction that is substantially orthogonal        to the first direction.-   2. The sensor mounting assembly of item 1 wherein the first roller    and second roller are oriented substantially orthogonal to each    other.-   3. The sensor mounting assembly of any one of items 1-2 including a    right angle plate that connects the second elongated frame member to    the first elongated frame member in a mutually orthogonal    arrangement.-   4. The sensor mounting assembly of any one of items 1-3 including a    third roller attached to the first elongated frame member, the third    roller configured to contact and roll upon a third surface of one of    the first, second, third and fourth vessels.-   5. The sensor mounting assembly of item 4, wherein the third roller    is oriented substantially parallel to one of the first roller and    second roller.-   6. The sensor mounting assembly of any one of items 4-5, including a    raising mechanism that lifts the third roller to the third surface.-   7. A sensor mounting assembly configured for use with a vessel    arrangement including at least first, second, third and fourth    vessels, the vessel arrangement disposed in a container in a    two-by-two stacked configuration having a central space, the sensor    mounting assembly including:    -   a top rail assembly attached to the container proximate a top of        the container and configured to position a first sensor        proximate the first vessel;    -   an upper interior rail assembly positioned in the central space        and configured to position a second sensor proximate the first        vessel and a third sensor proximate the second vessel;    -   a lower interior rail assembly positioned in the central space        and configured to position a fourth sensor proximate the third        vessel and a fifth sensor proximate the fourth vessel; and    -   a bottom rail assembly attached to the container proximate a        bottom of the container and configured to position a sixth        sensor proximate the fourth vessel.-   8. The sensor mounting assembly of item 7, including a bracket    configured to attach the top rail assembly to a sill of the    container.-   9. The sensor mounting assembly of any one of items 7-8, including a    cross bar attached to the first and second vessels.-   10. The sensor mounting assembly of item 9, including a raising    mechanism attached to the cross bar and configured to position the    upper interior rail assembly in the central space above the lower    interior rail assembly.-   11. The sensor mounting assembly of any one of items 7-10, wherein    at least one of the upper interior rail assembly and lower interior    rail assembly includes first and second rollers configured to    contact and roll upon the third and fourth vessels, respectively.-   12. The sensor mounting assembly of item 11, wherein the first and    second rollers are oriented substantially orthogonal to each other.-   13. The sensor mounting assembly of any one of items 11-12, wherein    the at least one of the upper interior rail assembly and lower    interior rail assembly includes a third roller configured to contact    and roll upon one of the first and second vessels.-   14. The sensor mounting assembly of item 13, wherein the third    roller is oriented substantially parallel to one of the first roller    and second roller.-   15. The sensor mounting assembly of any one of items 7-14, including    a bracket configured to attach the bottom rail assembly to a pipe of    the container.-   16. The sensor mounting assembly of any one of items 7-15, including    a sensor bracket configured to roll on a frame of the bottom rail    assembly and attach to the sixth sensor.-   17. A method of mounting first, second, third, fourth, fifth, and    sixths sensors for use with a vessel arrangement including at least    first, second, third and fourth vessels, the vessel arrangement    disposed in a container in a two-by-two stacked configuration having    a central space, the method including:    -   attaching a top rail assembly to the container proximate a top        of the container to position a first sensor proximate the first        vessel;    -   inserting an upper interior rail assembly into the central space        to position a second sensor proximate the first vessel and a        third sensor proximate the second vessel;    -   inserting a lower interior rail assembly into the central space        to position a fourth sensor proximate the third vessel and a        fifth sensor proximate the fourth vessel; and    -   attaching a bottom rail assembly to the container proximate a        bottom of the container to position a sixth sensor proximate the        fourth vessel.-   18. The method of item 17, including attaching a bracket of the top    rail assembly to a sill of the container.-   19. The method of any one of items 17-18, including raising the    upper interior rail assembly in the central space to position the    upper interior rail assembly above the lower interior rail assembly.-   20. The method of any one of items 17-19, wherein positioning the    sixth sensor includes rolling a sensor bracket on a frame of the    bottom rail assembly.

This summary is provided to introduce concepts in simplified form thatare further described below in the Detailed Description. This summary isnot intended to identify key features or essential features of thedisclosed or claimed subject matter and is not intended to describe eachdisclosed embodiment or every implementation of the disclosed or claimedsubject matter. Specifically, features disclosed herein with respect toone embodiment may be equally applicable to another. Further, thissummary is not intended to be used as an aid in determining the scope ofthe claimed subject matter. Many other novel advantages, features, andrelationships will become apparent as this description proceeds. Thefigures and the description that follow more particularly exemplifyillustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed subject matter will be further explained with reference tothe attached figures, wherein like structure or system elements arereferred to by like reference numerals throughout the several views. Itis contemplated that all descriptions are applicable to like andanalogous structures throughout the several embodiments.

FIG. 1 is a top and end perspective view of a pressure vessel assemblypositioned in a container, and having sensors positioned thereon usingan exemplary embodiment of a sensor mounting system.

FIG. 2 is a close-up view of a portion of FIG. 1, showing a sensor anddata acquisition box mounted relative to a pressure vessel.

FIG. 3 is a side perspective view of the pressure vessel assembly andmounting rail assemblies of the sensor mounting system, without thecontainer.

FIG. 4 is a close-up view of a portion of FIG. 3, taken from a differentviewing angle.

FIG. 5 is an end view of a pressure vessel assembly in a container, withan end wall panel of the container removed so that the pressure vesselsand sensor mounting rail assemblies can be seen therein.

FIG. 6 is a close-up end perspective view of a portion of FIG. 5.

FIG. 7 is a side perspective view of an exemplary top rail assembly.

FIG. 7A is an enlarged exploded view of the encircled portion in FIG. 7labeled “A.”

FIG. 7B is an enlarged exploded view of the portion of FIG. 7 that isencircled and labeled “B.”

FIG. 7C shows a reverse side of the top rail assembly of FIG. 7.

FIG. 7D is an enlarged exploded view of the portion of FIG. 7C that isencircled and labeled “D.”

FIG. 8 is a perspective view of an exemplary upper interior railassembly.

FIG. 8A is an enlarged view of the encircled portion “A” of FIG. 8.

FIG. 9 is a perspective view of an exemplary lower interior railassembly.

FIG. 9A is an enlarged view of the encircled area “A” of FIG. 9.

FIG. 9B is an enlarged view of the encircled portion “B” of FIG. 9.

FIG. 10 is a perspective view of an exemplary bottom rail assembly.

FIG. 11 is a partial view of a portion of the bottom rail assemblymounted to a pipe of the container.

FIG. 12 is a perspective view of an exemplary sensor bracket used on thetop, interior and bottom rail assemblies.

FIG. 13 is an exploded view of the sensor bracket of FIG. 12.

FIG. 14 is a front perspective view of an exemplary sensor brackethaving an attached sensor and roller plate.

FIG. 15 is a rear perspective view of the exemplary sensor bracketassembly of FIG. 14.

While the above-identified figures set forth one or more embodiments ofthe disclosed subject matter, other embodiments are also contemplated,as noted in the disclosure. In all cases, this disclosure presents thedisclosed subject matter by way of representation and not limitation. Itshould be understood that numerous other modifications and embodimentscan be devised by those skilled in the art that fall within the scope ofthe principles of this disclosure.

The figures may not be drawn to scale. In particular, some features maybe enlarged relative to other features for clarity. Moreover, whereterms such as above, below, over, under, top, bottom, side, end, right,left, vertical, horizontal, etc., are used, it is to be understood thatthey are used only for ease of understanding the description. It iscontemplated that structures may be oriented otherwise.

DETAILED DESCRIPTION

As a result of the principal stress state and anisotropic constructionof Type III and Type IV cylindrical composite pressure vessels (alsocalled pressure cylinders), several unique wave propagationcharacteristics are observed by MAE sensors. These principal stressstates are caused, for example, by the metallic load sharing liner onthe interior of Type III cylinders and the inherently asymmetriclaminate construction of Type IV composite pressure cylinders. From alaminated plate theory perspective, the non-symmetric laminate resultsin non-zero components of the coupling stiffness matrix (B_(ij)); from awave propagation perspective, such a result indicates that unlikeisotropic plates, pure extensional and flexure mode deformation will notbe observed.

A key component to optimizing the sensor spacing for the MAE testing ofcomposite pressure cylinders and ensuring full coverage of the cylinderis understanding the attenuation behavior of the composite laminate as afunction of the propagation angle and the frequency at which the wavepropagates. From experimental measurements and considerations of theprincipal stress state of the vessel, for an equivalent frequency, wavesare attenuated more severely at angles approaching the axial directionof the vessel. Conversely, waves are attenuated less severely in thehoop direction, a fact that can be exploited when determining sensorspacing and placement schemes of composite pressure cylinders.

To minimize the number of sensor locations necessary to fully cover avessel, increases in signal sensitivity and SNR (signal-to-noise ratio)can be realized through a Phased Array Modal Acoustic Emission (PA-MAE™)approach over traditional single-element MAE measurements. The increasein system sensitivity and SNR provided with PA-MAE™ are utilized indetermining sensor spacing in highly attenuative wave propagationmeasurements, as is common in composite pressure cylinders. Furthermore,it has been shown that accurate source location from a multiple elementarray is possible.

In light of the above discussion, sensor array placement that isadequately dense in the axial direction 60, but which simultaneouslytakes advantage of the less attenuative nature of wave propagation inthe hoop direction, is utilized to minimize the number of sensorplacement locations, while fully covering the pressure vessel.

Sensor arrays have been used to assess the structural integrity ofpressure vessels in laboratory settings. In the current state of theart, the pressure vessel is removed from its field application andshipped to a laboratory for testing. Thus, pressure vessels aretypically not tested when they are deployed in arrangements in use. Thisdisclosure is directed to a sensor mounting system that allows for thetesting of pressure vessels in the field, such as in an arrangement 20of four pressure vessels 22 contained within a container 24, as shown inFIG. 1. The disclosed system allows for requalification testing of thepressure vessels 22 out in the field by allowing testing sensors to bemanipulated in very compact spaces around the pressure vessels as theyare arranged in an actual use, such as in a shipping container, forexample.

In an exemplary embodiment, container 24 is a typical intermodalshipping container, such as one suitable for use with semi-trailertrucks, trains, cargo ships and barges. FIG. 1 shows the top portion ofan arrangement 20, the totality of which can be seen in FIG. 5. In FIG.1, the roof of the container 24 has been removed to allow access to atop portion of arrangement 20 of the pressure vessels 22.

As shown in FIGS. 1 and 3, different types of rail assemblies forholding the sensors are used in different areas of the container 24.Rail assemblies 32, 44, 46 and 48 allow for insertion of the sensorarrays into the confined areas within the shipping container 24 andaround the pressure vessels 22. For example, top rail assembly 32includes brackets 42 for resting upon a side wall 62 of a shippingcontainer 24 in which the arrangement 20 of pressure vessels 22 isplaced. Upper interior rail assembly 44 includes wheels thereon forrolling into the space 64 between the pressure vessels 22, with therollers or casters 56 rolling upon the upper wall surfaces of the twobottom pressure vessels 22. Once rolled into the space 64, the upperinterior rail assembly 44 is raised into position against the upper twopressure vessels 22 by cable 68 and hook 70, as shown in FIG. 6.Thereafter, the lower interior rail assembly 46 can be similarly rolledinto space 64. Two bottom rail assemblies 48 are attached by pipebrackets 82 to pipes 30 at the lower corners of container 24.Thereafter, sensor brackets 58 (having spacer bars 108 attached betweenadjacent sensor brackets 58) are rolled onto frame member 50 of bottomrail assembly 48 via rollers 84, as shown in FIGS. 10, 14 and 15.

As shown in FIGS. 1 and 2, in an exemplary embodiment, cross bars 26span across the top two pressure vessels 22 and include support rods 28.In container 24, a perforated pipe 30 may span a length (i.e., dimensionalong axial direction 60) of the container 24 at the top and/or bottomof each of the side walls 62 of container 24. In some cases, perforatedpipes 30 contain fire protection elements. In an exemplary embodiment,top rail assemblies 32 of an exemplary sensor mounting system arepositioned proximate top pipes 30. A plurality of sensors 34 andassociated data acquisition boxes 36 are arranged along a length (i.e.,dimension along axial direction 60) of each top rail assembly 32. In anexemplary embodiment, each sensor 34 is a PA-MAE sensor that isconfigured to be placed in contact with the outer cylindrical surface ofpressure vessel 22. As shown in the illustrations, an array of thesensors 34 is positioned along the surfaces of pressure vessels 22 inpredetermined locations to gather acoustic wave data relevant to eachpressure vessel 22.

FIG. 2 is a close-up view of a right-hand portion of FIG. 1, showing asensor 34 and its associated data acquisition box 36. To position sensor34 to obtain information on pressure vessel 22, an actuation device 38is actuated to move sensor 34 in direction 40, so that the sensingsurface of sensor 34 contacts the outer surface of pressure vessel 22with an appropriate coupling force. In exemplary embodiments, suitableactuation devices 38 include, for example, pneumatic cylinders, electricmotors, and magnetic actuators. In an exemplary embodiment, direction 40is substantially orthogonal to a tangent of the outer surface ofpressure vessel 22. In an exemplary embodiment, top rail assembly 32 issupported on container 24 by brackets 42.

In FIGS. 1 and 2, only the upper portion of an arrangement 20 of fourpressure vessels 22 is visible. FIG. 3 show the entire arrangement 20 offour pressure vessels 22, removed from container 24. While the disclosedmounting system is described with reference to a set of four pressurevessels 22, positioned in a two-by-two stacked arrangement, it iscontemplated that the various components of the disclosed mountingsystem can be applied to other arrangements of pressure vesselsincluding more or fewer pressure vessels, in different stackedconfigurations, and/or different vessel sizes. As shown in FIG. 3, anexemplary sensor mounting system includes two top rail assemblies 32, anupper interior rail assembly 44, a lower interior rail assembly 46, andtwo bottom rail assemblies 48. Each of these rail assemblies 32, 44, 46and 48 has a length that is suitable for the pressure vessels 22 to betested, and also configured for the container 24 in which the pressurevessel arrangement 20 is positioned. While sensors 34, data acquisitionboxes 36, actuation devices 38, and their associated electrical, signal,and fluid supply lines are not shown in some drawings for ease ofviewability, it is to be understood that they would be attached to thedescribed sensor mounting system in actual use. In an exemplaryembodiment, each of the rail assemblies 32, 44, 46, 48 carries the samenumber of sensors 34 and their corresponding actuation devices 38,evenly spaced along a length that is parallel to axial direction 60. InFIG. 3, for simplicity of illustration, not all of the devices 34, 36are shown on each of the rail assemblies 32, 44, 46 and 48.

In the illustrated embodiments, each of the pressure vessels 22 has arow of sensors 34 (mounted on rail assemblies 32, 44, 46, 48) ondiametrically opposed sides of the pressure vessel 22. Thus, in theillustrated embodiment, the rows of sensors 34 are arranged around eachpressure vessel 22 with a radial spacing of about 180 degrees. Such anarrangement 20 is particularly suitable for use with phased array MAEsensors. However, it is contemplated that additional rows of sensors 34(and corresponding rail assemblies) could be added, such as would besuitable with other types of sensors, such as the more traditionalsingle-element MAE sensors, or as vessel diameter, material attenuationbehavior, and other factors warrant. For example, additional railassemblies may be used to space rows of sensors around each pressurevessel 22 with a radial spacing of about 90 degrees. Moreover, where apressure vessel is removed from a container, additional flexibility isafforded, and a radial spacing between three rows of sensors around apressure vessel with a radial spacing of about 120 degrees is useful. Itis contemplated that still other radial spacings are suitable, such asmight be used with other types of sensors.

As shown in FIG. 4, each of upper interior rail assembly 44 and lowerinterior rail assembly 46 includes two t-slot aluminum frame members 50in an exemplary embodiment. Particularly suitable frame members 50 arecommercially available from 80/20 Inc. of Columbia City, Ind. In anexemplary embodiment, the two frame members 50 of each of upper interiorrail assembly 44 and lower interior rail assembly 46 are held in amutually orthogonal relationship by the affixation of each of framemembers 50 to an angle plate 52. Brackets 54 of each of interior railassemblies 44, 46 carries casters 56 thereon. As shown on lower interiorrail assembly 46, casters 56 are oriented to roll on the outercylindrical surfaces of the lower pressure vessels 22. Sensor mountingbrackets 58 are positioned on interior rail assemblies 44, 46 so thatactuation devices 38 mounted thereon will move the attached sensors intoposition in contact with the outer cylindrical surfaces of the pressurevessels 22.

Because the interior rail assemblies 44, 46 each include two frameelements 50, the frame elements of the interior rail assemblies 45, 46in some cases will be referred to with reference numerals 50 a and 50 b.However, it is to be understood that all references to frame member 50will also apply to frame members 50 a and 50 b, unless otherwiseindicated.

Upper interior rail assembly 44 has a plurality of casters 56 arrangedsimilarly to those described with reference to lower interior railassembly 46. To position the interior rail assemblies 44, 46 in thespace 64 between the four pressure vessels 22, in an exemplary method ofpositioning rail assemblies of an exemplary sensor mounting system, theupper interior rail assembly 44 is inserted into space 64 while thelower interior rail assembly 46 remains outside of arrangement 20. Upperinterior rail assembly 44 is inserted into space 64 proximate an end ofthe pressure vessels 22 by rolling the upper interior rail assembly 44on casters 56 on the cylindrical surfaces of the two bottom pressurevessels 22. Thus, the upper interior rail assembly 44 would occupyessentially the position shown as being occupied by the lower interiorrail assembly 46 in FIG. 4. After the upper interior rail assembly 44 isfully inserted into space 64, the upper interior rail assembly 44 israised into the position shown in FIG. 4 by a cable inserted throughloops 66, which are affixed to angle bracket 52 in an exemplaryembodiment. As shown in FIG. 6, an exemplary cable 68 is attached tosupport rod 28, which in turn is attached to cross bar 26. In anexemplary embodiment, an easily detachable connection between supportrod 28 and cable 68 is provided by hook 70. In the lifted position,another set of casters 72 is placed in contact with the cylindricalouter surfaces of the two upper pressure vessels 22.

After the upper interior rail assembly 44 is lifted into the positionshown in FIGS. 4 and 6, the lower interior rail assembly 46 can berolled into position as shown, with casters 56 contacting thecylindrical surfaces of the bottom two pressure vessels 22. As shown inFIG. 1, front wall panel 73 of container 24 has an opening 74 providedtherein to allow for the insertion of interior rail assemblies 44, 46into space 64 between the four pressure vessels 22 of arrangement 20. Toposition sensor 34 to obtain information on pressure vessel 22, anactuation device 38 is actuated to move sensor 34 in direction 40, sothat the sensing surface of sensor 34 contacts the outer surface ofpressure vessel 22 with an appropriate coupling force. In exemplaryembodiments, suitable actuation devices 38 include, for example,pneumatic cylinders, electric motors, and magnetic actuators. In anexemplary embodiment, direction 40 is substantially orthogonal to atangent of the outer surface of pressure vessel 22. While notillustrated, it is to be understood that a plurality of electricalpower, signal communication, and pneumatic air lines are connected tothe sensors 34, actuators 38 and associated data acquisition boxes 36mounted on the rail assemblies 32, 44, 46, 48.

FIG. 7 is a perspective view of an exemplary embodiment of top railassembly 32. FIG. 7A is an enlarged view of the portion of FIG. 7 thatis encircled and labeled “A.” FIG. 7B is an enlarged view of the portionof FIG. 7 that is encircled and labeled “B.” In FIG. 7, some of thesensor brackets 58, container brackets 42, and data acquisition boxbrackets 76 shown attached to frame member 50. Additionally, one each ofcontainer bracket 42, sensor bracket 58 and data acquisition box bracket76 are shown detached from frame member 50. A length of frame member 50(along axial direction 60) can be selected to suit a particular pressurevessel 22 to be assessed. Moreover, the number of sensor brackets 58 anddata acquisition box brackets 76 (and a corresponding number of sensors34 and data acquisition boxes 36) can be selected according to thelength and diameter of the pressure vessel 22, along with otherconsiderations such as the pressure vessel material composition and thetype of sensor 34 to be mounted. Each of the plurality of sensor mounts58 is preferably evenly spaced along a length of frame member 50 (i.e.,at equal intervals) in an exemplary embodiment. Such positioning alongthe length of frame member 50 can be adjusted in some embodiments bysliding and/or rolling the bracket 42, 58 or 76 along longitudinal slots78 of frame member 50. Moreover, the brackets 42, 58, 76 can be attachedto frame member 50 using fasteners such as plates, washers, screws, andbolts, for example.

FIG. 7C shows a reverse side of the top rail assembly 32 of FIG. 7. FIG.7D is an enlarged view of the portion of FIG. 7C that is encircled andlabeled “D.” As shown in FIGS. 7A, and 12-15, in an exemplaryembodiment, sensor bracket 58 includes arms 112 on opposed sides ofplates 102. Each arm 112 includes at least one hole 114 configured forthe passage of fastener 116, which secures sensor 34 between arms 112 ofsensor bracket 58. As shown in FIG. 7A, fasteners 134 pass through twoof holes 104 in plates 102 and connect to corresponding fasteners 136positioned within slot 78 of frame member 50. An actuation device 38 isheld in actuator containment space 100 and is configured to push uponsurface 118 of sensor 34 in direction 40. This action moves suitablesensor components into contact with the surface of pressure vessel 22.

As shown in FIGS. 7 and 7B, in an exemplary embodiment, containerbracket 42 includes a first portion 120 attached to frame member 50 withfastener 122, washer 124, and plate 126. Container bracket 42 alsoincludes a second portion 128 attached to the first portion 120 byfastener 130, to thereby clamp sill 132 of side wall 62 (labeled inFIGS. 1, 2 and 5) of container 24 between the first and second portions120, 128 of container bracket 42.

As shown in FIG. 7D, in an exemplary embodiment, data acquisition boxbracket 76 includes plate 138 having holes 140 for the passage offasteners 142, which attach to data acquisition box 36. Further, plate138 has holes 144 for the passage of fasteners 134, which connect tocorresponding fasteners 136 positioned within slot 78 of frame member 50(as discussed above with reference to FIG. 7A, for example).

FIGS. 13-15 show perspective and exploded perspective views of exemplaryembodiments of sensor bracket 58. An exemplary sensor bracket 58includes a centrally located actuator containment space 100, configuredto hold actuation device 38. Plates 102 includes holes 104 configured toaccept fasteners for attachment to frame member 50, as discussed abovewith reference to FIG. 7A. Additionally, referring to FIGS. 14 and 15,holes 104 may be used to accept fasteners (not shown) for attachment ofplate 106, which is in turn attached to rollers 84.

FIG. 8 is a perspective view of an exemplary embodiment of upperinterior rail assembly 44. On the left side of FIG. 8, in encircledportion “A,” some of the components such as caster bracket 54 and itsassociated caster 56, sensor bracket 58, data acquisition box bracket 80and its associated data acquisition box 36 are shown as detached fromframe members 50. However, these elements are illustrated as beingattached to frame members 50 in the un-encircled portion of FIG. 8. InFIG. 8, the sensor brackets 58 and data acquisition box brackets 80 ononly one of the frame elements 50 b are clearly visible. However, it isto be understood that a similar arrangement of sensor brackets 58 anddata acquisition box brackets 80 is also provided on the other frameelement 50 a. FIG. 8 also shows fluid manifold 110, to which fluid linesare attached for actuation of actuation devices 38 held in actuatorcontainment space 100 of sensor bracket 58.

FIG. 9 is a perspective view illustrating some components of anexemplary lower interior rail assembly 46. Because the sensor brackets58 are mounted on two frame members 50 a and 50 b, in some cases, thesensor brackets will be referred to with reference numerals 58 a and 58b. However, it is to be understood that all references to sensor bracket58 will also apply to sensor brackets 58 a and 58 b, unless otherwiseindicated. Sensor brackets 58 a are shown as attached to frame element50 a. Sensor brackets 58 b are shown as removed from frame element 50 b.In an exemplary embodiment, data acquisition box brackets 80 areattached to frame element 50 between adjacent sensor brackets 58.

FIG. 10 is a perspective view of an exemplary embodiment of bottom railassembly 48, which includes pipe brackets 82 attached to frame element50 proximate ends of the frame element 50. In an exemplary embodiment,sensor brackets 58 are attached to frame element 50 by rollers 84, shownin FIGS. 14 and 15. In an exemplary embodiment, each roller 84 isconfigured with a flange 86 that rolls along groove 78 of frame element50. In an exemplary embodiment, spacer bars 108 are positioned on frameelement 50 between adjacent sensor brackets 58 to facilitate accurateand consistent spacing intervals between adjacent sensor brackets 58(and therefore consistent spacing between sensors 34 in the mountedsensor arrays).

FIG. 11 is a perspective partial end view of bottom rail assembly 48secured to pipe 30 of container 24. Often, a container 24 will includefour pipes 30, the upper pipes 30 being visible in FIG. 1, and the lowerpipes 30 being visible in FIG. 3. In an exemplary embodiment, pipebracket 82 includes a first portion 88 attached to frame member 50 withfastener 90 and a second portion 92 attached to the first portion 88 byfasteners 94, to thereby clamp pipe 30 between the first and secondportions 88, 92 of pipe bracket 82. FIG. 11 further shows a two partclamp 96, fastened together by fastener 98, which is used to secure pipe30 to an interior of side wall 62 of container 24.

Referring to FIGS. 1, 10 and 11, for installation of bottom railassembly 48 in container 24, in an exemplary embodiment, only smallaccess openings 75 in an end wall panel 73 proximate the lower cornersof container 24 are required for insertion of frame element 50 havingfirst portion 88 of pipe bracket 82 fixed thereto. Frame element 50 ofbottom rail assembly 48 is secured inside container 24 by clampingsecond portion 92 and first portion 88 of pipe bracket 82 togetheraround pipe 30.

Thereafter, the plurality of sensor brackets 58, spaced apart from eachother by intervening spacer bars 108, are attached to frame element 50by moving rollers 84 from one end of frame element 50 toward the otherend of frame element 50. To position sensor 34 to obtain information onpressure vessel 22, an actuation device 38 is actuated to move sensor 34in direction 40, so that the sensing surface of sensor 34 contacts theouter surface of pressure vessel 22 with an appropriate coupling force.In exemplary embodiments, suitable actuation devices 38 include, forexample, pneumatic cylinders, electric motors, and magnetic actuators.In an exemplary embodiment, direction 40 is substantially orthogonal toa tangent of the outer surface of pressure vessel 22.

After gathering and processing information from sensors 34 and dataacquisition boxes 36, actuation devices 38 may be activated to retractsensors 34 away from the respective surfaces of pressure vessel 22 sothat rail assemblies 32, 44, 46, 48 can be removed from container 24 ina reverse method of their installation. The rail assemblies 32, 44, 46,48 can then be deployed on a different pressure vessel arrangement 20for assessment of the structural integrity and estimated usefulremaining life of a different set of pressure vessels 22.

For example, for removal of bottom rail assembly 48, in an exemplaryembodiment, the connected line of multiple sensor brackets 58 andattached intervening spacer bars 108 can be pulled off one end of frame50. Then, two portions 88, 92 of pipe bracket 82 can be disconnected,allowing frame 50 to be pulled out opening 75 in end wall 73 ofcontainer 24.

Lower interior rail assembly 46 can be rolled via casters 56 on the twobottom pressure vessels 22, out of opening 74 of end wall 73 ofcontainer 24, to thereby remove lower interior rail assembly 46 fromspace 64 between the pressure vessels 20. For removal of upper interiorrail assembly 44, cable 68 is detached from hook 70 and upper interiorrail assembly 44 is lowered so that casters 56 contact the two bottompressure vessels 22. Upper interior rail assembly 44 can be rolled viacasters 56 on the two bottom pressure vessels 22, out of opening 74 ofend wall 73 of container 24, to thereby remove upper interior railassembly 44 from space 64 between the pressure vessels 20.

For removal of upper rail assembly 32 from container 24, two portions120, 128 of container bracket 42 can be disconnected, allowing theirremoval from sill 132 of side wall 62 of container 24. Frame 50 can belifted out of container 24 so that a roof of container 24 can bereplaced.

Although the subject of this disclosure has been described withreference to several embodiments, workers skilled in the art willrecognize that changes may be made in form and detail without departingfrom the scope of the disclosure. In addition, any feature disclosedwith respect to one rail assembly 32, 44, 46, 48 may be incorporated inanother rail assembly 32, 44, 46, 48, and vice-versa.

The invention claimed is:
 1. A method of mounting a first sensor with avessel arrangement including at least first, second, third and fourthvessels, the vessel arrangement disposed in a container in a two-by-twostacked configuration having a central space, the method including:inserting a first interior rail assembly into the central space;positioning a first sensor on the first interior rail assembly proximatethe first vessel; positioning a second sensor on the first interior railassembly proximate the second vessel; moving the first sensor intocontact with the first vessel upon actuation in a first direction; andmoving the second sensor into contact with the second vessel uponactuation in a second direction.
 2. The method of claim 1, including:attaching a top rail assembly to the container proximate a top of thecontainer by attaching a bracket of the top rail assembly to a sill ofthe container; and positioning a third sensor on the top rail assemblyproximate the first vessel.
 3. The method of claim 1, including raisingthe first interior rail assembly in the central space.
 4. A method ofmounting a first sensor with a vessel arrangement including at leastfirst, second, third and fourth vessels, the vessel arrangement disposedin a container in a two-by-two stacked configuration having a centralspace, the method including: inserting a first interior rail assemblyinto the central space; positioning a first sensor on the first interiorrail assembly proximate the first vessel attaching a bottom railassembly to the container proximate a bottom of the container; androlling a sensor bracket on a frame of the bottom rail assembly.
 5. Themethod of claim 1 comprising: attaching a top rail assembly to thecontainer proximate a top of the container; and positioning a thirdsensor on the top rail assembly proximate the first vessel.
 6. A methodof mounting a first sensor with a vessel arrangement including at leastfirst, second, third and fourth vessels, the vessel arrangement disposedin a container in a two-by-two stacked configuration having a centralspace, the method including: inserting a first interior rail assemblyinto the central space; positioning a first sensor on the first interiorrail assembly proximate the first vessel inserting a second interiorrail assembly into the central space; and positioning a second sensor onthe second interior rail assembly proximate the third vessel.
 7. Themethod of claim 6 comprising positioning a third sensor on the secondinterior rail assembly proximate the fourth vessel.
 8. The method ofclaim 1 comprising: attaching a bottom rail assembly to the containerproximate a bottom of the container; and positioning a third sensor onthe bottom rail assembly proximate the fourth vessel.
 9. The method ofclaim 1 wherein the second direction is substantially orthogonal to thefirst direction.
 10. The method of claim 1 wherein inserting the firstinterior rail assembly into the central space includes rolling the firstinterior rail assembly upon at least one of the first, second, third andfourth vessels.
 11. The method of claim 1 wherein inserting the firstinterior rail assembly into the central space includes rolling the firstinterior rail assembly upon two of the first, second, third and fourthvessels.
 12. The method of claim 3 wherein raising the first interiorrail assembly comprises using a hook attached to a cross bar.
 13. Themethod of claim 3, including inserting a second interior rail assemblyin the central space after raising the first interior rail assembly. 14.The method of claim 13 wherein inserting the second interior railassembly into the central space includes rolling the second interiorrail assembly upon at least one of the first, second, third and fourthvessels.
 15. The method of claim 4 comprising using a pipe bracket toattach the bottom rail assembly to the container.
 16. The method ofclaim 4, wherein the sensor bracket is one of a plurality of sensorbrackets, the method comprising attaching a spacer bar between twoadjacent sensor brackets of the plurality of sensor brackets.